KiwiRail and New Zealand Police have both issued warnings to motorists following impatient driver's crossing over train tracks while barriers are down.

The warning comes after three motorists were spotted zig-zagging around the barriers on Monday, while barriers were down and alarm bells were sounding.

KiwiRail group general manager Katie McMahon says the barriers are there to protect people and it's both dangerous and illegal to drive around them when they are down.

'Not staying behind the barriers puts motorists, and their passengers as well as our staff at serious risk.

'While it may appear that a train has stopped and the way is clear, there is the risk of another train coming from the opposite direction.

'Trains may have to halt briefly for operational reasons and we can appreciate that it can be frustrating to have to wait at the barrier arms.

"Safety is the higher priority and always will be, and there is no excuse for driving around barrier arms,” says Katie.

New Zealand Police have also agree with what KiwiRail have said.

'At barrier arms, you must stop until the arms are lifted again,” says a police spokesperson.

'Driving around barrier arms is incredibly dangerous – even if a train has passed, there may be a second train or a train coming from the other direction.

'And just as running a red light is dangerous, so is trying to race the bells, lights or barrier arms – a train can't stop suddenly.

'As a driver it's also important to ensure there is plenty of clear space on the other side of the train tracks for your vehicle, and any long load you're carrying or trailer you're towing, before you drive over the crossing.”